Electric switch



March 30, 1937.

E. C. HORTON ELECTRIC SWITCH File'd May 10, 1953 1 2g? BMW Erwin C.fiorcom %QWMM W Patented Mar. 30, 1937 UNITED STATES ELECTRIC SWITCHErwin C. Horton, Hamburg, N. Y., assignmto Trico Products Corporation,Buffalo, N. Y.

Application May 10, 1933, Serial No. 670,356

10 Claims.

This invention relates to a switch especially adapted for causing anintermittent flashing or flickering of a signal light, such as the stoplight of a motor vehicle signalling system. The invention has to do moreparticularly with that type of switch wherein a thermostatic action isprovided for causing a repeated making and breaking of the signalcircuit.

Thermostatic switches heretofore designed have comprised bi-metallicelements which, when subjected to an electric current, caused a breakingof the circuit. The constructions heretofore designed have caused moreor less arcing of the current across the switch points during thebreaking of the circuit, and also because of their fabrication they havebeen of impractical design.

The object of the present invention is to provide a simple andpractically designed make and break switch suitable for use in motorvehicle signalling systems, though not restricted to such use, and onewherein the making and breaking of the circuit is affected in a definitepositive manner.

In the drawing Fig. l is a plan view of the switch for etiecting theintermittent opening and closing of a circuit, the 'casing cover havingbeen removed.

Fig. 2 is a longitudinal section through the switch, with the cover inposition.

Fig. 3 is a transverse section therethrough.

Fig. 4 is a detailed perspective of a portion of the snap-over action ofthe switch, the parts shown being separated.

Referring more particularly to the drawing, the flicker switch I l,embodying the present invention and adapted to be connected to thesignalling or other circuit for efiecting the intermittent actuation ofthe signal, is depicted herein as comprising a base 48, a pair ofterminal members 49 and 50, which may be in the form of binding posts,an anchor plate 5i to which the binding post 49 is electricallyconnected, a second plate 52 to which the binding post 50 is likewiseconnected, and means for making and breaking circuit connections betweenthe two terminal members. The anchor plate 5| is provided with 3. lug 53to which one end of a resistance element or wire 54 is anchored, theopposite end of the wire being connected to an arm of a lever 56. Theresistance element will lineally expand, when heated from the currentpassing therethrough, and contract or shorten as it cools when thecurrent is reduced or interrupted. The lever is pivoted on a fulcrum pin51 and is in electrical connection with the plate 52 and carried by ashaft 50 journaled therein. The pin is mounted eccentrically on thisshaft so that by turning the latter, as with a screw driver engaged inthe exteriorly accessible kerf the position of the lever pivot may bevaried to obtain adjustment of the interval of darkness in a mannerhereinafter referred to. A spring 58, interposed between the lever and apost 59, acts to urge the lever in a counter-clockwise direction forholding the resistance wire 54 under tension.

The lever is provided with an arm 6| comparatively longer than the arm55 so that any movement imparted to the latter will be enlarged at theouter end of the arm 6|. Such amplified movement is utilized to actuatea. circuit making and breaking or circuit shunting member 62. Thisbreaker or shunting member is pivoted in seats 53 on a bracket 63 and isconnected to the free outer end of the long arm 6| by a coil spring 64.The coiled spring is moved back and forth across a median or dead centerposition by the arm 5| so that the breaker member 62 will likewise bemoved from one to the other of its two limit positions as determined bythe two limit' stops and 56. The limit stop 66 is adjustably mounted onthe plate 5|, being carried on the member 62 to plate 52. When the partsare disposed in the dotted or broken line position of Fig. 1, whereinthe breaker member 62 is spaced from the contact point 56 and is engagedagainst the companion stop member 55, as indicated at 62', this path forthe current is interrupted so that all of the current passes through theresistance element 54. In this position of the parts the longer arm 6|oi the lever has moved substantially to the position 5 I so as todispose the spring 64 on the opposite side of the median position of thebreaker member.

The resistance wire may be passed over the screw 51 to provide a drag orfriction suflicient to hold it against unauthorized turning. A casingcover H encloses the switch mechanism, when desired, and a bracket Ilaprovides a convenient .means for mounting the same.

The operation of the flicker switch is as follows: Assuming that theparts are in the dotted position depicted in Fig. 1, with the breakermember 62 disposed against the stop 85 so as to necessitate the entirecurrent flow passing through the resistance element 54, the latter willbecome heated and expand in a linear direction.

This expansion releases the lever 56 for limited counter-clockwisemovement under the urge of the spring 58 so that the longer arm 6| ismoved to bring the spring 64 to the opposite side of its median positionand snap the breaker member 62 to its full line position against thecontact point 66. Immediately upon the breaker member 62 engaging thecontact point 66 the fiow of current will follow the path of lesserresistance through contact point 66 and breaker member 62, therebypermitting the resistance element 54 to cool and lineally shorten orcontract. This contraction of the resistance element exerts a pull onarm 55 and swings the lever in a clockwise direction against the tensionof spring 58 so as to move the longer arm substantially to the positionindicated by the dotted showing 8|. During this arm movement the spring64 is moved across the median position to snap the breaker member 62away from the contact point 66 and thereby again break the current paththerethrough. Consequently, the entire current flow will again passthrough the resistance element to lineally expand the same, and thecycle of operation just described will again be repeated.

With the current passing through the contact or breaker member 62, thelatter being held against the fixed contact or shoulder 65 to whichposition said member 52 is constantly urged by the spring means composedof the two springs 58 and 64 with the interposed or connecting lever arm6!, the current will then be of sufficient strength to illuminate thesignal, such as an incandescent light bulb (not shown). Consequently,the flicker switch will operate the signal intermittently, or duringthose intervals when the main current is passing through the contactingparts 62 and 66, during which intervals the thermostatic element 54 iscooling. When such element has cooled sufliciently to shorten orcontract to such an extent as to constrain and counteract the normalurge of the spring means 58, GI, 64, to hold the contact member 62against the contact or stop shoulder 66, the line of spring force ofsuch spring means which acts upon the contact member 62 will be shiftedby the cooling thermostatic wire to the opposite side of the pivotalmounting of such contact member 62 and cause the parts 62 and B6 toseparate with a snap action. Such spring means will hold the member 62against the stop shoulder 65, as above stated.

The intervals of illumination and darkness of an illuminated signal maybe varied when desired. For varying the interval of illumination, or theinterval of electrical operativeness of the signals, the screw 61 isthreaded outwardly to withdraw the contact 66. This permits the breakermember 62 to move farther away from its median position and therebyrequire a greater movement of the free end of arm 6| to bring the spring64 across dead center. For varying the interval of darkness, theeccentric mounting of the fulcrum pin 5! permits adjustment of the leverpivot by turning the shaft 60 in either direction. By such adjustment ofthe pin 5'! an increased tension will be placed on the resistance wire,and also, during this adjustment, the lever will move clockwise todispose the free end of the arm 61 further from the median position ofthe breaker 62.

This disposition of the free end, at a greater distance from such medianposition, will require a greater return movement of the arm to bring thespring 64 back across the dead center or median position. Consequently,the interval of darkness, or the interval of inoperativeness of thesignal, will be increased.

What is claimed is:

1. An intermittently operating switch for electric circuits comprisingspaced stop members, a circuit connection with one of said members, acontact member movable back and forth between said stop members foropening and closing a circuit through the specified one of said stopmembers, an oscillatable actuator, means for pivotally mounting theactuator for back and forth movement, resilient means connecting thecontact member to said actuator and movable by the latter back and forthbeyond a median position to dispose the resilient means at oppositesides of such median position for effecting the back and forth movementsof said contact member, means for adjusting the pivotal axis of saidactuator, thermally expansive means connected to said actuator formoving the latter in one direction of oscillation, circuit connectionsfor such thermally expansive means, and means for urging the actuator inthe opposite direction of oscillation when permitted by said thermallyexpansive means.

2. An intermittently operating switch for electric circuits comprisingspaced stop members, a circuit connection with one of said members, acontact member movable back and forth between said stop members foropening and closing a circuit through the specified one of said stopmembers, an oscillatable actuator, means for pivotally mounting theactuator for back and forth movement, resilient means connecting thecontact member to said actuator and movable by the latter back and forthbeyond a median position to dispose the resilient means at oppositesides of such median position for effecting the back and forth movementsof said contact member, means for adjusting the pivotal axis of saidactuator, thermally expansive means connected to said actuator formoving the latter in one direction of oscillation, circuit connectionsfor such thermally expansive means, and means for urging the actuator inthe opposite direction of oscillation when permitted by said thermallyexpansive means, the other of said stop members being in electricalconnection with said thermally expansive means, and said contact memberbeing in electrical connection with said thermally expansive means forestablishing a shunt circuit about said thermally expansive means whensaid contact member is in abutting relation with said other stop member.

3. An intermittently operating switch for electric circuits comprisingspaced stop members, a circuit connection with one of said members, acontact member movable back and forth between said stop members foropening and closing a circuit through the specified one of said stopmembers, an oscillatable actuator, means for pivotally mounting theactuator for back and forth movement, resilient means connecting thecontact member to said actuator and movable by the latter back and forthbeyond a median position to dispose the resilient means at oppositesides of such median position for effecting the back and forth movementsof said (ill contact member, said actuator adjacent its pivotal mountinghaving oppositely extending arm portions, a thermally expansive elementconnected to one of said arm portions for moving the actuator in onedirection of oscillation, a spring means connected to the other of saidarm portions for urging the actuator in the opposite direction ofoscillation whenpermitted by said thermally expansive element, and meansfor adin justing the pivotal axis of said actuator to vary theresponsiveness of said actuator to said thermally expansive element.

4. A switch for signalling systems, comprising spaced contact members,means for making and breaking the circuit"therebetween, said.

means including a breaker element, a snap action for moving the breakerelement back and forth between an open circuit position and a closedcircuit position, said snap action including a member movable back andforth between two positions, a resistance element for providing analternate path of flowfor the electric current between'said contactmembers when said breaker member is moved to open circuit posi- :15tion, said resistance element being thermally expansible andcontractible, and, an operative connection between said movable memberand said resistance element whereby the latter will effect movement ofsaid movable member in one direction.

5. A switch for flickering signal lights and the like, comprising spacedterminal member, a thermal expansion element electrically connected toone terminal member, a movably mounted actuator in electrical connectionwith the companion terminal member and to the opposite end of saidthermal expansion element for being moved in one direction thereby, saidactuator being resiliently urged in the opposite di- 10 rection andmovable in such direction when permitted by said thermal expansionelement, said element and said actuator being in a constantly closedcircuit between said terminal members, and a normally open shunt circuitabout said thermal expansion element, said shunt circuit including amovable switch contact member movable by said actuator during thermalexpansion of said element for closing such normally open shunt circuitand thereby shunting the circuit about said element to permit thecooling of the latter and the return of said actuator, means supportingsaid contact member for operation to opposite sides of a dead centerposition, and means automatically urging the contact member intocontacting relation upon movement of said member beyond dead centerposition in either direction.

6. A switch for flickering signal lights and the like, comprising asupport, a pair of stop shoul- (io ders, a contact member movable backand forth between said stop shoulders, an actuator movable back andforth, resilient means connecting the contact member to said actuatorand movable by the latter back and forth beyond a me- ;5 dian positionto dispose the resilient means at opposite sides of such median positionto effect the back and forth movements of the contact member between therespective stop shoulders, thermally expansive means connected to saidactuator for moving the latter in one direction,

and spaced terminal members electrically connected through saidthermally expansive means for the passage of current through the latterto effect expansion thereof, one of said stop 7;; shoulders being inelectrical connection with one of said terminal members, said contactmember being in electrical connection with the other of said terminalmembers for establishing a shunt circuit about the thermally expansiveelement when said contact member is in abutting relation withsaid,specifled stop shoulder.

7. A switch for flashing signal circuits, and the like, comprising asupport, a pair of stop shoulders, a. contact member movable back andforth between said stop shoulders for making and breaking a shuntelectric circuit through one shoulder, resilient means normally actingto urge the contact member toward such one shoulder to a circuit closingposition and including a spring adapted to have its line of spring forceshifted to move the contact member away from said one shoulder andtoward the companion shoulder for breaking the circuit, and thermallyexpansible means connected to said resilient means for controlling theoperation thereof and normally acting therethrough to hold the contactmember toward said companion shoulder for breaking the circuit, saidthermally expansible means being electrically connected at one endportion to said one shoulder and at its opposite end portion to saidcontact member in a permanently closed circuit paralleling the shuntcircuit through the contact member and one shoulder, said thermallyexpansible means expanding in the presence of a broken shunt circuit topermit said resilient means functioning in establishing the shuntcircuit.

8. A switch for flashing signal circuits, and the like, comprising asupport, a pair of stop shoulders, a contact member movable back andforth between said stop shoulders for making and breaking a shuntelectric circuit through one shoulder, resilient means normally actingto urge the contact member toward such one shoulder to a circuit closingposition and including a spring adapted to have its line of spring forceshifted to move the contact member away from said one shoulder andtoward the companion shoulder for breaking the circuit, thermallyexpansible means connected to said resilient means for controlling theoperation thereof and normally acting therethrough to hold the contactmember toward said companion shoulder for breaking the circuit, saidthermally expansible means being electrically connected at one endportion to said one shoulder and at its opposite end portion to saidcontact member in a permanently closed circuit paralleling the shuntcircuit through the contact member and one shoulder, said. thermallyexpansible means expanding in the presence of a broken shunt circuit topermit said resilient means functioning in establishing the shuntcircuit, and means for adjusting the responsiveness of said thermallyexpansible means.

9. A switch for flashing signal circuits, and the like, comprising asupport, a pair of stop shoulders, a contact member movable back andforth between said stop shoulders for making and breaking a shuntelectric circuit through one shoulder, resilient means normally actingto urge the contact member toward such one shoulder to a circuit closingposition and including a spring adapted to have its line of spring forceshifted to move the contact member away from said one shoulder andtoward the companion shoulder for breaking the circuit, and thermallyexpansible means connected to said resilient means for controlling theoperation thereof and normally acting therethrough to hold the contactmember toward said companion shoulder for breaking the circuit, saidthermally expansible means being electrically connected at one endportion to said one shoulder and at its opposite end portion to saidcontact member in a permanently closed circuit paralleling the shuntcircuit through the contact member and one shoulder, said thermallyexpansible means expanding in the presence of a broken shunt circuit topermit said resilient means functioning in establishing the shunt cirtomove the contact member away from said one shoulder and toward thecompanion shoulder for breaking the circuit, and thermally expansiblemeans connected to said resilient means for controlling the operationthereof and normally acting therethrough to hold the contact membertoward said companion shoulder for breaking the circuit, said thermallyexpansible means being electrically connected at one end portion to saidone shoulder and at its opposite end portion to said contact member in apermanently closed circuit paralleling the shunt circuit through thecontact member and one shoulder, said thermally expansible meansexpanding in the presence of a broken shunt circuit to permit saidresilient means functioning in establishing the shunt circuit, saidsupport having a bearing and said contact member being detachably andpivotally mounted in the bearing for such back and forth movement, andsaid spring being connected directly to said contact member and actingto hold the latter in the bearing.

' ERWIN C. HORTON.

